Abstract:

The invention relates to a connection element, in particular a plate nut,
comprising a base body for attachment of an arbitrary component to a
metallic planar object, in particular to a sheet metal.
According to the invention, the base body comprises a securement portion
the cross-sectional geometry of which deviates from a circular shape, the
securement portion being at least partially positively receivable in a
deformation in the sheet metal. The base body is, by means of a holding
device, secured in the deformation against dropping out.
In an alternative embodiment of the connection element, wherein unilateral
accessibility to the sheet metal is sufficient, the holding device is
formed by bead portions in a shaft area of the base body, which are
plastically deformed into a bead by pull-out of a threaded bolt that is
screwed into a thread portion.
In accordance with a further embodiment the holding device is formed by a
threaded nut engageable on the underside with the base body of the
connection element or/and snappable onto the same, bilateral
accessibility to the sheet metal however being required.

Claims:

1. A connecting element, in particular a speed nut, comprising a basic
body, for connecting a component to a metallic planar structure, in
particular a metal sheet, characterised in that the basic body has a
securing portion, the cross-sectional geometry of which differs from the
circular shape and which can be positively received, at least in regions,
in an opening, in the metal sheet, the basic body being secured against
falling out by means of a holding device in the opening.

2. The connecting element according to claim 1, wherein the
cross-sectional geometry of the securing portion has at least two
portions with a different curvature, in particular is configured in an
oval or elliptical manner to prevent a rotation of the basic body in the
opening.

3. The connecting element according to claim 1, wherein the holding device
is a bead which can be configured by a plastic deformation of a bead
portion of the basic body.

4. The connecting element according to claim 3, wherein the bead portion
has a hollow cylindrical cross-sectional geometry.

5. The connecting element according to claim 3, wherein the basic body has
a threaded portion, into which a threaded mandrel can be screwed, it
being possible to shape the bead by a movement in opposite directions
between the threaded mandrel and a counter support.

6. The connecting element according to claim 1, wherein an end portion of
the basic body is open, or closed for sealing.

7. The connecting element according to claim 1, wherein the basic body has
a collar, which is positively received, at least in regions, in a
peripheral crimp or a countersink of the opening.

8. The connecting element according to claim 7, wherein the collar
terminates flush with the metal sheet.

9. The connecting element according to claim 1, wherein the basic body has
a collar, which rests on the metal sheet forming a shoulder.

10. The connecting element according to claim 1, wherein the connecting
element is formed by a metallic material, in particular an aluminium
alloy, a titanium alloy, a high-grade steel alloy or titanium.

11. The connecting element according to claim 7, wherein the collar with
the bead portion, on the one hand, and the threaded portion, on the other
hand, are separate components, which can be connected to one another, in
particular can be coaxially plugged together, the bead portion and/or the
collar being formed by a metallic material which is softer in comparison
to the threaded portion.

12. The connecting element according to claim 1, wherein the holding
device is a threaded nut, which can be latched underneath to the basic
body.

13. The connecting element according to claim 12, wherein at least two
latching noses, which can be brought into engagement with at least two
recesses in the threaded nut, are arranged on the basic body.

14. The connecting element according to claim 12, wherein the basic body
has a hole for introducing a fastening bolt for a component to be
fastened.

15. The connecting element according to claim 12, wherein the basic body
and/or the threaded nut are formed by a plastics material, in particular
a fibre-reinforced plastics material.

Description:

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001]This application claims the benefit of U.S. Provisional Application
No. 61/089,726, filed Aug. 18, 2008, the entire disclosure of which is
herein incorporated by reference.

FIELD OF THE INVENTION

[0002]The invention relates to a connecting element comprising a basic
body for connecting a component to a metallic planar structure, in
particular a metal sheet.

[0003]Rivet nuts are generally used to implement screw connections on thin
metal aircraft sheets. A typical rivet nut comprises a metal support
sheet, into which a nut is snapped or latched to connect the component.
To complete the connection, the metal support sheet is then riveted to
the fuselage cell structure.

[0004]The drawbacks in this type of rivet nuts are inter alia the stress
concentration owing to the two rivets, the increased space requirement
because of the multi-part mode of construction and the weight caused by
this. Regardless of this, a riveting of the metal support sheets using
flush head rivets requires a minimum thickness of the metal sheet, which
generally exceeds the statically necessary minimum dimension and this is
usually the greatest drawback.

[0005]Furthermore, fastening systems with rivet nuts are known
("ForceTec®"), in which the metal support sheet is part of a flange
bushing, which is installed in the bolt hole. As a result, a relatively
low weight is achieved with simultaneously low fatigue behaviour over the
entire service life of the connection. The drawbacks, however, in this
system are the multi-stage work sequence and the high costs.

SUMMARY OF THE INVENTION

[0006]The object of the invention is to provide a connecting element which
substantially avoids the drawbacks mentioned above in the fastening of
known rivet nuts to thin metal sheets.

[0007]This object is achieved by a connecting element with the features of
claim 1.

[0008]Since the basic body has a securing portion, the cross-sectional
geometry of which differs from the circular shape and which can be
positively received, at least in regions, in an opening in the sheet
metal, the basic body being secured against falling out by means of a
holding device in the opening, a high resistance capacity of the
connecting element is produced relative to torques, which are caused, for
example, when screwing in a fastening bolt to connect an external
component or by the fastened component. The connecting element is
prevented from rotating by a non-round securing portion, which is located
positively, at least in regions--but preferably with the provision of a
complete positive fit--in the opening of the metal sheet formed to
correspond with this. The opening which is non-round, for example
elliptical, oval or, at least in two portions, curved as desired, within
the metal sheet may be produced by means of a punching tool, for example.

[0009]The holding device prevents the connecting element from falling out
in the vertical direction. To place the connecting element in a first
embodiment variant, a one-sided access to the metal sheet is sufficient,
so that it is possible, for example, to fasten the connecting element to
hollow bodies, hollow profiles or similar components within the fuselage
cell structure of an aircraft. In addition, the outlay for assembly is
reduced in comparison to multi-component fastening elements.

[0010]Regardless of this, the connecting element according to the
invention, in contrast to many previously known technical solutions in
this field, can be universally used for sheet metals with a material
thickness of between 0.5 mm and 5 mm.

[0011]In one embodiment variant, the connecting element is formed by a
metallic material, for example a high-strength aluminium alloy, a
titanium alloy, a high-grade steel alloy or pure titanium. A further
embodiment variant can be produced by fibre-reinforced plastics
materials, in particular.

[0012]A development of the connecting element provides that the
cross-sectional geometry of the securing portion has at least two
portions with a different curvature, in particular, is configured in an
oval or an elliptical manner, to prevent the basic body rotating in the
opening.

[0013]Owing to the non-round securing portion and the correspondingly
configured opening, a high torque resistance of the connecting element in
the metal sheet is achieved with a simultaneously good resistance
capacity of the connection produced against symptoms of fatigue over the
entire service life of the aircraft.

[0014]According to a further advantageous configuration, it is provided
that the holding device is formed by a bead, which can be configured by a
plastic deformation of a bead portion of the basic body.

[0015]The positional fixing of the connecting element in the metal sheet
takes place in that the sheet metal is clamped between the bead extending
underneath and a collar of the connecting element cooperating at the top
with the metal sheet. As a result of the irreversible plastic deformation
process to form the bead, an automatic detaching of the connecting
element, for example owing to the effect of shocks, fatigue symptoms or
the action of tensile forces, is ruled out. Moreover, a high resistance
capacity relative to symptoms of fatigue of any type is provided by the
bead.

[0016]According to a further advantageous configuration, the unshaped bead
portion has a hollow cylindrical cross-sectional geometry.

[0017]As a result, the threaded mandrel used to expand the bead portion
may have a standard, circular cross-sectional geometry.

[0018]A further advantageous development of the connecting element
provides that the basic body has a threaded portion, into which a
threaded mandrel can be screwed, wherein the bead can be shaped by a
movement in opposite directions between the threaded mandrel and a
counter support.

[0019]As a result, placing of the connecting element is made possible by
relatively simply constructed tools which are light and can also be
handled manually.

[0020]To create the bead, a threaded mandrel is screwed into the
connecting element and a counter support is placed on the upper side of
the metal sheet. The threaded mandrel is then moved or drawn by means of
a suitable tool in the opposite direction by to the counter support, with
the formation of a peripheral bead below the metal sheet taking place as
a result of a plastic deformation of a bead portion of the connecting
element. The tool can move the thread mandrel, for example, by means of
an electric actuating drive or by means of a hydraulic drive unit. The
tool may have a device for the preadjustment of the necessary tensile
force as a function of a metal sheet thickness. On reaching the
preselected tensile force, the tightening process is automatically ended.
In an advantageous manner, the counter support is configured as an
integral component of the tool used to tighten the threaded mandrel. The
threaded mandrel is received, for example, by means of a chuck on the
pulling tool in order to be able to replace and clamp different threaded
mandrels.

[0021]A further advantageous configuration of the connecting element
provides that an end portion of the basic body is open, or closed for
sealing.

[0022]The open configuration of a threaded portion has the advantage, in
particular, that longer fastening bolts can be screwed from the upper
side of the metal sheet into the connecting element, as long as these do
not come into undesired contact on the inside with a further component.
The closed embodiment variant of the lower threaded portion allows the
provision of a hermetically sealed connection. For this purpose, the
lower threaded portion of the connecting element is preferably formed
hemispherically, but may also have a surface shape which differs from
this.

[0023]A development of the connecting element provides that the basic body
has a collar, which is positively received, at least in regions, in a
peripheral crimp or a countersink of the opening.

[0024]Owing to the collar, in conjunction with the bead produced by a
plastic deformation, the positional fixing of the connecting element
takes place primarily in the vertical direction. In the case of metal
sheets with a small material thickness of, for example, less than 2 mm,
for secure fastening of the connecting element, the production of a crimp
running around the non-round opening is advantageous, as owing to the
securing portion in conjunction with the opening reveal, no adequately
high prevention of rotation can be achieved. However, the effect of the
securing portion is assisted by the crimp with the collar positively
resting therein. In the case of metal sheets with a higher material
thickness, instead of a crimp, the edge region of the opening may be
provided with a countersink. The function of the countersinking
corresponds here to the purpose of the crimp.

[0025]According to a further advantageous development, it is provided that
the collar of the connecting element terminates flush with the upper side
of the metal sheet.

[0026]This allows a level upper side of the metal sheet to be achieved in
the region of the fastening element and this may be desired, for example
for aerodynamic or aesthetic reasons. Deviating from this, the collar of
the connecting element may also be configured in such a way that it rests
above the upper side of the metal sheet with the formation of a shoulder,
in other words, is not countersunk. This alternative embodiment of the
connecting element is advantageous, in particular, to transfer higher
forces.

[0027]A further configuration provides that the collar with the bead
portion, on the one hand, and the threaded portion, on the other hand,
are separate components, which can be connected to one another, in
particular can be coaxially plugged together, the bead portion and/or the
collar being formed by a metallic material which is softer in comparison
to the threaded portion.

[0028]As a result, a mechanically highly loadable connection can be
achieved between the connecting element and an external component by
means of a screwed-in connecting bolt and, simultaneously, the tensile
force required to shape the peripheral bead may be reduced in a defined
manner by the use of a softer metal.

[0029]A further advantageous configuration of the connecting element
provides that the holding device is a threaded nut which can be latched
underneath to the basic body.

[0030]This embodiment of a connecting element, in contrast to the first
embodiment variant according to claim 1, is configured with a threaded
nut which can be latched to a basic body and therefore latched thereto
underneath, two-sided access to the metal sheet being required, however.
The connection between the basic body also positively received at the top
in a non-round opening of the metal sheet to the (snap-in) threaded nut
arranged in the region of the lower side of the metal sheet takes place,
for example, by means of two latching noses, which cooperate with lateral
recesses in the threaded nut. The advantage of this embodiment variant
is, in particular, that a rapid, tool-free fastening is possible and, in
addition, the connecting element can also be detached again if necessary.

[0031]The connecting element according to this embodiment variant is
advantageously formed by plastics material, in particular a
fibre-reinforced plastics material.

[0032]Further advantageous embodiments of the connecting element are
described in the following claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0033]In the drawings:

[0034]FIG. 1 shows a side view of the non-shaped connecting element
positioned in an opening in a metal sheet,

[0035]FIG. 2 shows a sectional view of the non-shaped connecting element
inserted in a metal sheet along the section line II-II in FIG. 1,

[0037]FIG. 4 shows a view from below of the shaped connecting element
according to FIG. 3,

[0038]FIG. 5 shows a schematic cross-sectional view of a two-part and
non-shaped embodiment variant, inserted in a metal sheet, of the
connecting element,

[0039]FIG. 6 shows the variant of the connecting element according to FIG.
5 in the shaped state,

[0040]FIG. 7 shows a cross-sectional view of a further two-part embodiment
variant of the connecting element with a basic body and a threaded nut
for snapping in,

[0041]FIG. 8 shows a view from below of the embodiment variant of the
connecting element according to FIG. 7,

[0042]FIG. 9 shows a plan view of the threaded nut for snapping in
according to FIGS. 7, 8.

DETAILED DESCRIPTION OF THE DRAWINGS

[0043]The same structural elements in each case have the same reference
numeral in the drawings.

[0044]FIG. 1 shows a non-sectional side view of the unshaped connecting
element inserted in an opening, while FIG. 2 shows the connecting element
in the same state, but illustrated in a cross-sectional view along the
section line II-II in FIG. 1.

[0045]A connecting element 1 or a universal speed nut configured according
to the invention for different sheet metal thicknesses inter alia has a
basic body 2, which is inserted in a metal sheet 3. A non-round opening 4
is introduced into the metal sheet 3 and the inner edge region thereof is
provided with a peripheral crimp 5, the level of which in relation to an
upper side 6 of the metal sheet 3 is countersunk by a depth 7 in order to
achieve a flush termination of the connecting element 1 with the upper
side 6 of the metal sheet 1. Preferably, the contour of the non-round
opening 4 follows an elongate oval or an ellipse to achieve the desired
prevention of the connecting element from rotating in the metal sheet
3--optionally in conjunction with an optional crimp or countersinking.
Basically, the opening 4 may be provided with virtually any conceivable
geometric shape, although curvature radii which are too small or edges
which are too sharp should be avoided in view of fatigue prevention. The
contour of the opening 4 preferably has at least two portions each with a
different curvature. The opening 4 can be introduced into the metal sheet
3, for example, by means of a suitable punching tool, not shown in the
figures.

[0046]A collar 8 of the connecting element 1 positively rests on the crimp
5, at least in regions. For this purpose, the collar 8 is peripherally
provided with a slightly inclined bevel 9, so a flush termination with
the upper side 6 of the metal sheet 3 is ensured.

[0047]The basic body 2 furthermore has a non-round securing portion 10,
the peripheral contour of which positively rests on the opening 4, at
least in regions, in order to prevent the connecting element 1 from
rotating in the metal sheet 3. For this purpose, the securing portion 10
has, for example, an oval, an elliptical or other curvature of contour,
which corresponds with the opening contour. A bead portion 11 adjoins the
securing portion 10 towards the bottom. The bead portion 11 is the region
of the connecting element 1 in which a predefined, plastic deformation is
implemented to fasten the connecting element 1 in the metal sheet 3 by
means of a threaded mandrel, not shown in FIGS. 1 to 4, and a pulling
tool, in a similar manner to "pop riveting tongs". A threaded portion 12
with an inner thread 13 also adjoins the bead portion 11. The inner
thread 13 is, on the one hand, used for screwing in a threaded mandrel
(cf. FIGS. 5, 6) to allow the shaping of the connecting element 1 by the
action of a tensile force on the threaded mandrel and the bead portion
and, on the other hand, to screw in a connecting bolt, also not shown,
for fastening an external component to the metal sheet 3. The threaded
portion 12 passes into an end portion 14. The end portion 14, as
illustrated in FIG. 1 to 3, may have a hemispherical form or a level form
(cf., in particular FIGS. 5, 6) in order to simultaneously bring about a
hermetic sealing or making tight of the connecting element 1. The
connecting element 1 can thus also be used, for example, for fastening
components to thin-walled fuel or hydraulic tanks or the like.
Alternatively, the end portion 14 may simply be open at the bottom, in
other words practically be an extension of the threaded portion 12. In
this constellation, a fastening bolt can be screwed completely through
the threaded portion 12.

[0048]Only the collar 8 or flange and the securing portion 10 have a
contour which differs from the circular shape. The bead portion 11, the
threaded portion 12 and the end portion 14, on the other hand, have a
substantially hollow cylindrical cross-sectional geometry.

[0049]FIGS. 3, 4 illustrate the connecting element 1 in the plastically
shaped final state. FIG. 3 corresponds--except for the shaping process
that has taken place--to the view of FIG. 2, while, in FIG. 4, a plan
view from below of the already shaped connecting element 1 according to
FIG. 3 is shown.

[0050]The bead portion 11 is transformed by plastic deformation into a
bead 15. The sheet metal 3 is firmly clamped between the bead 15 and the
collar 8. The connecting element 1 is prevented from carrying out an
undesired rotation during the screwing in of a connecting bolt into the
threaded portion 12 by the non-round securing portion 10 in conjunction
with the positive fit between the collar 8 and the crimp 5. The
connecting element 1 is prevented from being pulled out or falling out
when tensile stresses result from the bead 15 in conjunction with the
collar 8. The hemispherical end portion 13 ensures the hermetic sealing
of the connecting element 1 relative to gases and/or liquids passing
through.

[0051]The crimp 5 may be advantageously used, in particular in the case of
a metal sheet 3 with a small material thickness, as a countersinking of
the opening 4 in the case of small thicknesses is generally not possible.
In contrast, in the case of metal sheets with a high material thickness,
a flush connection of the connecting element 1 can be achieved without
problems, for example by conical countersinking. Alternatively, it is
possible in the case of small metal sheet thicknesses to equip the collar
8 of the connecting element 1, instead of the bevelled or slightly
chamfered embodiment according to FIG. 1 to 4, with a rectangular
cross-section, which rests, when the connecting element 1 is positioned,
on the upper side 6 of the metal sheet 3 with the formation of a
shoulder. The advantage of this variant is, in particular, that a collar
with a rectangular cross-section can absorb higher tensile or pressure
loads than the peripherally slightly chamfered or bevelled collar 8.

[0052]The connecting element 1 integrally configured in the variant
according to FIG. 1 to 4 is preferably formed by a metallic material, for
example an aluminium alloy, a titanium alloy, a high-grade steel alloy or
pure aluminium or pure titanium.

[0053]FIGS. 5 and 6 illustrate, in a schematic cross-sectional view, a
variant of the connecting element 1 according to the invention which, in
contrast to the embodiment variant according to FIG. 1 to 4, is two-part.

[0054]A connecting element 16 has a basic body 17, which is provided to be
received in a metal sheet 18. Introduced into the metal sheet 18 is,
again, an opening 19 with a crimp 20 running in the edge region, with
regard to the more detailed description of which reference is made to the
embodiment in the description of FIG. 1 to 4. In order to achieve a flush
termination, in the ideal case, of the connecting element 1, a depth 22
of the crimp 20 is selected such that it coincides approximately with a
material thickness of the collar 23. The collar 23 is, in contrast to the
embodiment according to FIGS. 1 to 4, not bevelled or inclined inwardly,
but has an approximately rectangular cross-section with merely rounded
edges. A securing portion 24, with the provision of a preferably complete
positive fit, rests on the opening 19 to ensure the required prevention
of the connecting element 16 from rotating in the metal sheet 18. A bead
portion 25, in which the actual plastic deformation takes place during
the fastening process of the connecting element 16 in the metal sheet 18,
adjoins the securing portion 24 of the collar 23. The collar 23, in the
unshaped state of the connecting element 16, can be pushed onto a
threaded portion 26 which, in contrast to the embodiment according to
FIG. 1 to 4, in this variant, is a separate component. The threaded
portion 26, in a known manner, contains an inner thread 27 and is
provided with a planar end portion 28 for hermetic sealing.

[0055]To place the connecting element 16, a threaded mandrel 29 is firstly
screwed into the threaded portion 26, as indicated by the opposing rotary
arrows and a counter support 30 coaxially surrounding the threaded
mandrel 29, for example, is placed on the upper side 21 of the metal
sheet 18. To carry out the shaping process, the threaded mandrel 29 and
the counter support 30 are moved in opposite directions to one another
with the application of a tensile force Ftensile, so the plastic
deformation of the bead portion 25 into a bead 31 takes place. Apart from
the primary shaping of the bead portion 25, a slight shaping of an upper
edge 32 of the threaded portion 26 occurs, which leads to a shaping of a
peripheral interstice 33, which positively rests on an outwardly directed
inner bevel 34 of the collar, so the threaded portion 26 is secured
against falling out of the collar 23.

[0056]A significantly softer and therefore easier to shape material is
preferably used for the collar 23 than for the threaded portion 26, so
the shaping process is facilitated and, simultaneously, a mechanically
more highly loadable connection becomes possible between the threaded
portion 26 and a fastening bolt to be screwed therein for an external
component. The possibility of a different material selection for the
collar 23 and the threaded portion 26 is the central advantage of this
embodiment variant compared to that according to FIG. 1 to 4.

[0057]Both the threaded mandrel 29 and the counter support 30 may be
integral components of a pulling tool, not shown in more detail and
preferably operable by hand. To receive and clamp the threaded mandrel
29, the pulling tool has suitable, fully automatic clamping devices. The
pulling tool is preferably hydraulically and/or electrically driven, a
force measuring device indicating the current tensile force, and an
open-loop and closed-loop control device allowing, as a function of the
force measurement values, an automatic ending of a successfully completed
shaping process and the adjustment of different limit values for the
tensile force Ftensile for various connecting elements.

[0058]FIG. 7 to 9 illustrate, in a highly schematic or part sectional
view, a further embodiment variant of the connecting element according to
the invention.

[0059]FIG. 7 shows a schematic cross-sectional view in principle of a
complete connecting element with a basic body and a (snap-in) threaded
nut, FIG. 8 illustrates a view from below of the connecting element
according to FIG. 7, but without a threaded nut, and FIG. 9 finally
illustrates, in an isolated manner, the threaded nut in a plan view. In a
further continuation of the description, reference is simultaneously made
to FIG. 7 to 9.

[0060]A connecting element 35 inter alia comprises a basic body 36 with a
threaded nut 37. The threaded nut 37 is received, with the provision of a
preferably complete positive fit, in an opening 38 which is in turn
non-round, in other words deviating from the circular shape, this opening
also being provided in the edge region with a crimp 39. The, for example,
oval or elliptical opening 38 and the crimp 39 may be configured in a
metal sheet 40, for example by punching and/or so-called "nippling in" or
"crimping in". Owing to this positive fit, at least in regions, between
the basic body 36 and the opening 38 or the crimp 39 and the collar 43,
rotation of the basic body 36 when screwing a fastening bolt, not shown,
into the threaded nut 37 is prevented. With regard to the detailed
forming of the opening 38 and the crimp 39, reference is made to the
explanation already given with respect to FIG. 1 to 6.

[0061]A depth 41 of the crimp 39 corresponds approximately to a height 42
of a collar 43 of the basic body 36. The basic body 36 is prevented from
falling through the opening 38 by means of the collar 43 which rests, at
least in regions, on the crimp 39. A thread-free cylindrical hole 44 is
introduced into the basic body 36 and is used to guide the fastening bolt
through. Two latching noses 45, 46 configured integrally with respect to
the basic body 36 and arranged therebelow, as holding devices, may be
connected in a latching manner to the (snap-in) threaded nut 37 by simply
snapping into two correspondingly configured recesses 47, 48 and prevent
the threaded nut 37 from falling out when the fastening bolt is
completely unscrewed. The basic body 36 also has a securing portion 49 by
means of which the basic body 36 is reliably prevented from rotating in
cooperation with the opening 38 configured positively with respect to
this, at least in regions. The threaded nut 37 has a threaded portion 50,
which is provided with an inner thread 51. Because of the snap-in
mechanism, the connecting element 35, in comparison to the other
embodiment variants, does not need a shapeable bead region to provide a
bead. The securing of the threaded nut 37 against falling out takes place
in that the crimp 39 is clamped between the collar 43 of the basic body
36 and a contact face 52 of the threaded nut. The contact face 52 has an
approximately square basic face with slightly bevelled edges, the contact
face 52 being selected to be significantly larger than a face of the
cylindrical hole 44 to prevent the threaded nut 37 from being pulled
through or falling down in the event of a tensile loading of the
connecting element 35. In contrast to the previous embodiment variants of
the connecting element 35, in the connecting element 35 according FIG. 7
to 9, access to the metal sheet 40 on both sides is necessary, however,
to allow the snapping of the nut 37 from the lower side onto the basic
body 36 inserted beforehand from the other side of the metal sheet 40
into the opening 38.

[0062]The connecting element 35, in accordance with the previous
embodiment variants, may be formed by a metallic material and/or,
differing therefrom, may also be formed by a plastics material having a
fibre reinforcement, in particular.

[0063]In particular if an electric contact is to be produced by means of
the connecting element 35 between the metal sheet 40 and a connecting
bolt screwed into the threaded nut 37, it is recommended that the contour
of the opening 38 and, accordingly, that of the crimp 39 be matched to a
rectangle with rounded edges and slightly curved sides, as a contact
face, not shown, between the basic body 36, which is electrically
conductive in this case, with the collar 43, on the one hand, and the
crimp 39 or the metal sheet 40, on the other hand, is increased by this
and consequently electric line losses are reduced in comparison to the
shape according to FIG. 7 to 9. As a result of the relatively angular
contour, in this case approximating an elongate rectangle, of the opening
38, resistance to fatigue symptoms (so-called "fatigue") is impaired in
this application, however.